Latch mechanism



April 26, 1955 G. wARTlAN 2,707,124

LATCH MECHANISM Filed Nov. 21, 1951 IIIA vlilllillllll. P 1 r l Zi) INVENTOR g We my ATTORNEY United States Patent O LATCH MECHANISM George Wartian, St. Clair Shores, Mich.

Application November 21, 1951, Serial No. 257,475

6 Claims. (Cl. 292-280) This invention relates to latch mechanisms for hinged doors, particularly automobile doors.

It is well known that automobile doors as at present made in the United States are locked from the outside by a key lock and are latched by a spring latch which is released by turning a handle or pressing a button on the outside. On the inside, these doors are usually locked by pushing a button or turning a handle. These locks for inside operation can invariably be released manually, which permits children to unlock the doors while the car is in motion, sometimes causing accidents. Also, a sudden stop of an automobile may pitch a passenger forward and in his helpless movement such a passenger may hit a door handle, thus opening the door and falling out of the car.

The principal object of my invention is to provide a safety attachment which will make it impossible to un lock from the inside a locked automobile door, while permitting release of the door from the outside by pushing a button or other operating element.

Other objects are to provide a safety attachment of the character indicated which is inexpensive to manufacture, easy to install, requires no substantial change in the conventional lock to which it is attached, is positive in operation, and will have a life as long as the lock itself.

The above and other objects are attained by the mechanism which is shown in the accompanying drawings as illustrative of numerous mechanisms embodying the invention.

In said drawings:

Fig. l is a fragmentary elevation of an automobile door lock, showing in dotted lines another position of certain parts;

Fig. 2 is a similar view showing the safety attach ment in inactive position, also showing in dotted lines another position of certain parts;

Fig. 3 is a view like Fig. 2 but showing the safety attachment in active position;

Fig. 4 is a section on line 4-4 of Fig. 2;

Fig. 5 is a section on line 5--5 of Fig. 2; and

Fig. 6 is a detail in perspective of the safety latch element which is added to the lock.

Referring particularly to the drawings, I have shown a well known type of door lock particularly illustrated in the I. H. Roethel Patent No. 2,538,913, issued January 23, 1951, and only such parts as are necessary to an understanding of this invention are shown in the present drawings.

On the inner door panel 11, which is partially shown in phantom, a case plate 12 is secured by screw bosses 13. The case plate 12 terminates at its inner edge 1n a flange 14 facing the inner door panel 11. The latch device further includes a rotatable toothed latch or bolt 15 positioned at the outer face of the case plate 12 and having an integral projecting shaft or shank 16 extending through an aperture in the case plate and having a bearing in the annular flanged edge 17 dening this aperture, while the inner end of shank 16 is flattened as at 18 and extends through a correspondingly shaped aperture in a rotatable toothed detent engaging member or ratchet member 19. The bolt 15 and the ratchet member 19 are rigidly secured as by a lock washer 20 so as to turn together. The rotatable bolt 15 is formed with a number of radially projecting equally spaced teeth 21 so as to provide a gear type latch. The ratchet member 19 is also formed ICC with a number of teeth 22 which correspond in number to the teeth 21. A four-armed detent 23 is pivotally mounted on a shoulder rivet 24 secured to the case plate 12. Detent 23 includes a downwardly extending arm 25 which cooperates with the teeth 22 of the ratchet member 19 to hold the ratchet member and hence the bolt 15 locked against rotation in door releasing direction. Associated with the detent 23 is a detent-actuating lever 26 which is pivoted at its lower end upon a shoulder rivet 27 secured to the case plate 12. Pivoted at 28 to lever 26 near the upper end thereof is a detent-operating link 29 having an extension 30 overlying and normally slidably engageable with the upper end of an upwardly extending arm 31 of detent 23. Link 29 is formed on its lower edge with an abutment or shoulder 32 adapted to engage the upper end of the detent arm 31 when the link 29 is shifted inwardly by swinging lever 26 inwardly or to the left as the parts are viewed in Figs. 2 and 3.

Detent 23 further includes an arm 3.3 which engages a rubber bumper or stop 34 so as to silence impact of the detent arm 25 against the sides of the teeth 22 when the ratchet member 19 is rotated in a clockwise direction, as viewed in Figs. 2 and 3, during closing of the door. A coil spring 35 anchored to a stud 36 (which is secured to the case plate 12) urges the detent arm 25 against teeth 22. Lever 26 is urged toward its normal position, shown in Fig. 2, by means of a coil spring 37 anchored to shoulder rivet 27 and having an arm 39 pressing against ange 40 which is integral with lever 26. A plunger 41 is actuated by any suitable manually operable means, such as a push button or handle, not shown, located on4 the outside of the door, and the inner end of plunger 41 engages flange on the opposite side thereof from coil spring arm 39, thereby permitting swinging of lever 26 and associated parts against the resistance of spring 37.

To permit manual control of the lock from inside the door, a knob 45 is xed to the upper end of a vertically shiftable rod or plunger 46 which extends upwardly through the garnish molding (not shown) inside the glass panel of the door, also not shown. The lower end of rod or plunger 46 is pivotally connected at 47 with an arm 48 of a lever 49 which is pivotally mounted on a shoulder rivet 50 txed to flange 14. Lever 49 has an arm 51 terminating in a rounded or enlarged end 52 lying within a channel-shaped projection 53 of a slide 54. This slide is guided in its sliding movements on flange 14 by means of upper and lower headed guide studs 55, 56 extending through vertical guide slots 57, 58, respectively, in the slide. The fourth arm 31a of detent 23 extends through a slot 34a provided in one edge of slide 54 and hence arm 31EL may swing with the detent without moving Slide 54. Obviously pushing down on knob 45 will swing lever 49 counterclockwise, as the parts are viewed in Fig. 4, which will move slide S4 upwardly, while pulling up on the knob will force the slide downwardly. Where a key is used to lock the door from the outside, the slide 54 will have spaced lugs 59, 60 at its lower end pivotally receiving the rounded endl 61 of a crank arm 62 which is fixed to the square portion 63 of a key-actuated shaft, said shaft being connected to the cylinder of any conventional cylinder lock (not shown) controlled by turning a key. By inserting the key in the lock and turning the key, crank arm 62 is swung to shift the slide 54 vertically in one direction or the other, thereby shifting the detentoperating link 29 into and out of engagement with detent arm 31.

Also pivotally mounted on shoulder rivet 50 is a bell crank lever 65 (Fig. 4) one arm 66 of which extends downwardly to a pivotal connection 67 with a generally horizontal operating link 68. As more fully disclosed in said Roethel patent, link 68 is moved back and forth by manipulation of a button or handle (not shown) on the inside of the door. Bell crank lever 65 also has an arm 69 Whose outer end is engaged on the underside by a safety latch element to be described. Arm 69 will engage a lug 54b projecting outwardly at right angles to slide 54 to move the slide 54 downwardly, when the slide is in its uppermost position (Fig. 3

and dotted lines in Fig. 4) and when the bell crank lign/H465 is swung clockwise as the parts are viewed in Without attempting to show or describe other clements of the known type of lock identified above, the added parts which make up thc safety attachment will now be described.

Pivoted as at 75 upon the case plate 12 is a latch lever 76, which may thus swing in a vertical plane between the left hand position (Fig. 3) and the right hand position shown in Fig. 2. Latch lever 76 is generally speaking a fiat sheet metal part, and it fits between the case plate 12 and detent 23. An L-shaped spring 77, fixed at one end to the case plate, has its free end resiliently and frictionally engaging the upper extremity of latch lever 76 at all times, and in the position of Fig. 2 acts as a stop and holder for the latch lever, which is received within the acute angle of the L-shaped spring. Flange 14 serves as a stop to limit swinging of the latch lever in the opposite direction. Near its upper end latch lever 76 has an outwardly projecting lug or arm 73 which is in position to be engaged by a shoulder 32a on detentoperating link 29. See Fig. 3. Near its lower, pivoted end, latch lever 76 has an extension arm 79 adapted to be engaged by the arm 33 of the detent, as will be understood from Fig. l..

To operate the safety attachment, one should push down on knob 45, which moves slide 54 upwardly to the position of Fig. 3, then push the button or operate the handle which moves plunger 4l inwardly. Detent-operating link 29 will then engage lug 78 and will swing the latch lever 76 to the left or to the position of Fig. 3. In this position a shoulder 80 (which is an integral part of the latch lever) will engage directly under arm 69 of bell crank lever 65 and said bell crank lever cannot be swung by the inside button or handle operating through link 68. Therefore, so far as the door-releasing parts on the inside of the car are concerned, the door is locked and cannot be unlocked, either accidentally or deliberately.

To disengage the safety lock, button 45 should be pulled up, which moves slide 54 down, and then the operating element on the outside of the car door is moved to cause plunger 41 to move inwardly or from the full line position of Fig. 2 to the dotted line position. Shoulder 32 on link Z9 will then engage detent arm 31 as indicated in Fig. l, swinging detent 23 counterclockwise, which causes detent arm 33 to engage arm 79 of latch lever 76, thus swinging the latch lever into the position of Fig. 2, where it remains because of the retaining spring 77. The conventional door locks or latches my then be operated in the usual manner.

From the foregoing description it will be clear that the safety attachment is very simple, is easily made and installed, and in no way interferes with the conventional lock nor does it require changes therein except for the installation of the attachment. Use of the attachment will obviate accidents and injuries to passengers.

What I claim is:

l. In an automobile door locking mechanism of the type which has a case plate, a bolt rotatably mounted on the case plate, a ratchet member fixed to the bolt, a pluralarmed detent pivotally mounted on the case plate and having one of its arms engaging one of the teeth of the ratchet member, a spring mounted on the case plate and forcing said arm against said tooth, a` slide mounted on the case plate for limited sliding movements in opposite directions, a manually operable mechanism for moving the slide in opposite directions, an inside door operating mechanism, an outside door operating mechanism including a plunger, a lever pivoted near one end to the case plate, a spring secured to the case plate and urging the lever to press against the end of the plunger, a detentoperating link pivoted to the lever near the area where the plunger engages the lever, said link having an extension overlying and normally slidably engageable with the upper end of a second arm of the plural-armed detent, said link also having a shoulder adapted to engage the upper end of said second detent arm when the link is shifted inwardly by swinging said lever through the intermediation of said plunger, the improvement which consists in the provision of a latch lever pivoted at one end upon the case plate, stop means for limiting the swinging of said latch lever in opposite directions, said latch lever having an army and said link having a shoulder engageable with said latch lever arm, said link extension being so engaged by said slide that movement of the slide by said manually operable mechanism will swing said link on its pivot to be disengaged from said second detent arm and to engage the latch lever arm with said shoulder, said latch lever also having an extension arm engageable by a third arm of the plural-armed detent, said latch lever further having a shoulder engaging a part of the inside door operating mechanism to prevent movement of said part when the latch lever is in locking position.

2. The invention defined in claim l, wherein the inside door operating mechanism includes a generally horizontal operating link having a pivotal connection at one end with one arm of a bell crank lever which is pivoted on the case plate, the other arm of said bell crank lever being engaged on the underside by said latch lever shoulder when the parts are locked, said slide having a lug also engageable by said other arm of said bell crank lever to permit moving said slidedownwardly by rocking of aild bell crank lever through said horizontal operating 3. The invention defined in claim l, wherein the means for limiting the swinging of said latch lever in opposite directions include a ange integral with and at right angles to the main body of said case plate, said fiange being contacted by one edge of said latch lever when the latch lever is in locking position, and an L- shaped spring fixed at one end to the case plate and having its free end resiliently and frictionally engaging the upper extremity of the latch lever at all times, the latch lever being received within the acute angle of the L- shaped spring and being held and stopped by said spring when the latch lever is in unlocking position.

4. The invention defined in claim l, wherein the inside door operating mechanism includes a generally horizontal operating link having a pivotal connection at one end with one arm of a bell crank lever which is pivoted on the case plate, the other arm of said bell crank lever being engaged on the underside by said latch lever shoulder when the parts are locked, said slide having a lug also engageable by said other arm of said bell crank lever to permit moving said slide downwardly by rocking of said bell crank lever through said horizontal operating link; and the means for limiting the swinging of said latch lever in opposite directions include a flange integral with and at right angles to the main body of said case plate, said flange being contacted by one edge of said latch lever when the latch lever is in locking position, and an L- shaped spring fixed at one end to the case plate and having its free end resiliently and frictionally engaging the upper extremity of the latch lever at all times, the latch lever being received within the acute angle of the L-shaped spring and being held and stopped by said spring when the latch lever is in unlocking position.

5. In combination with an automobile door locking mechanism having an inside latch-operating mechanism including a bell crank lever, and an outside latch-operating mechanism including a plunger, a lever swung by the plunger, a spring pressing against said lever in opposition to the thrust of the plunger to return the lever and plunger after such swinging, and a plural-armed detent swung by the lever when the lever is swung by the plunger, a case plate on which the bell crank lever, the lever and the plural-armed detent are each pivotally mounted, a slide mounted to reciprocate on the case plate, operatorcontrolled means to reciprocate said slide, a latch lever pivoted at one end upon said case plate and lying between the case plate and the plural-armed detent and having an integral arm engageable by one of the arms of the detent, a detent-operating link pivotally connected to said lever and engaging another arm of the detent when the plunger moves said lever inwardly, said detentoperating link having an extension which has a sliding and pivotal connection with said slide, so that the slide when reciprocated will swing said detent-operating link, said latch lever having a projecting arm or lug engageable by said detent-operating link when moved in one direction by said plunger, said latch lever also having a shoulder which is directly engaged with an arm of said bell crank lever to prevent door-releasing movement thereof when the latch lever is in active or locking position, the detent arm which engages the latch lever moving it to inactive or unlocking position when said detent is rocked on its pivot axis by manipulation of said detentoperating link through said lever and plunger.

6. The invention defined in claim 5, wherein there is a spring secured to the case plate and said spring engages the free end of the latch lever at all times and holds said latch lever against movement after the latch lever has moved a certain distance in one direction, the support having means engaged by the latch lever to stop further movement of the latch lever after moving a certain distance in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 

